Plex connect: Improve queue loading performance (#2735)

Plex connect: Improve queue loading performance (#2735)

* Plex connect: Improve queue loading performance

Start playback immediately with first track while loading remaining tracks
in background. This reduces perceived latency when playing queues from Plex.

Changes:
- Load and play first track immediately when queue is requested
- Fetch remaining tracks concurrently in background task
- Broadcast timeline update after first track starts

* Plex connect: applied copilot suggestion

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* Plex connect: fixed task creation

* Plex Connect: added await clause on line 715

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: Marvin Schenkel <marvinschenkel@gmail.com>